MVC5 Razor 值不能为 null 或为空。 参数名称：名称

Question

Source error: Line 22: @Html.TextBoxFor(model => model.DailyCurrencyRates___BuyingCurrency, new { @id = "test", @class = "form-control" })

I am stuck on this issue for days and cannot get round this error. I simply want to render a partial view with the items for parent class. below is my code: Please ask for more info if needed.

Controller

public ActionResult AddRecord(int index)
{
  return PartialView("_AddItem", new ForexItem { Index = index});
}

Parent View

@foreach (ForexItem item in Model.ForexItems)
{
    Html.RenderPartial("_AddItem", item);
}

Partial View

@model F.Models.Entities.ForexItem

@Html.TextBoxFor(model => model.DailyCurrencyRates___BuyingCurrency, new { @id = "test", @class = "form-control" })

Model

public partial class ForexItem
 {
        public int ID { get; set; }

        [NotMapped]
        [StringLength(1000)]
        [Display(Name = "Buying")]
        public string DailyCurrencyRates___BuyingCurrency { get; set; }

        [NotMapped]
        public int Index { get; set; }
}

Answer 1

I obtained that same vague, obscure error when I increased the number of underscores in a model property name from 1 to 2. Note that the error did not occur for the LabelFor Helper directly before the TextBoxFor helper, but just in the TextBoxFor helper, same as you got. (I notice your property name ("DailyCurrencyRates___BuyingCurrency") has 3 underscores.) It then went away when I removed the extra underscore from the property name. It was as though with the extra underscore, Razor could not find the property name, so it just searched for (generic) "name" instead, which it also could not find.

Answer 2

It may be a typo, but it seems to me that you should change Model.ForexItems to Model.ForexItem - no s. Based on your submitted code. … or maybe just use Model since you already put ForexItem in as that?

Parent View

@foreach (ForexItem item in Model)
{
    Html.RenderPartial("_AddItem", item);
}